Index mechanism



Jan. 31, 1967 E. R. BEMAN 3,301,097

INDEX MECHANISM Filed March 31, 1965 2 Sheets-Sheet 1 FIG. I

INVENTOR. E4 ROY BEMAN aw w. m

Jan, 31, 1967 E. R. BEMAN 3,301,097

INDEX MECHANISM Filed March 51, 1965 2 Sheets-Sheet 2 United StatesPatent York Filed Mar. 31, 1965, Ser. No. 444,268 Claims. (Cl. 74820)The present invention relates to a mechanism for intermittently indexingthe work spindle of a gear generating machine and for generally similarpurposes.

The invention provides a simple mechanism capable of indexing with highaccuracy in the rapid and yet smooth manner characteristic of Genevamotions. Indexing is effected and the mechanism then is locked up by theaxial shifting, preferably by fluid pressure, of a single unit whichconstitutes the driven element of the Geneva motion.

A mechanism according to the invention comprises a carrier, a spindlerotatable in the carrier, a Geneva driven wheel co-rotatable with thespindle and having equiangularly spaced radial slots and also havingsimilarly spaced clutch teeth, the carrier having mating clutch teeth,at Geneva driver rotatable in the carrier on an axis parallel to thespindle and having a drive pin engageable in the slots of the wheel,said driver being adapted to advance the wheel by one pitch upon eachrotation thereof in which the pin engages one of said slots, and meansto shift the wheel axially in the carrier between (a) a first positionwherein the clutch teeth of the wheel and carrier are engaged and thewheel is unengageable by the driver and (b) a second position whereinthe clutch teeth of the wheel and carrier are disengaged and the pin ofthe driver is engageable with said slots.

A preferred embodiment of the invention is shown in the accompanyingdrawings, wherein:

FIG. 1 is a vertical section through the housing of the mechanism, withthe lower portion of the index carrier appearing in elevation;

FIGS. 2 and 3 are detail sections in planes 22 and 33 of FIG. 1,respectively through the Geneva and the tooth clutch elements; and

FIG. 4 is a side view, partly in section approximately in the planesdesignated 44 in FIG. 1.

Referring to FIG. 1, the housing, which in this instance is the workhead of a bevel gear generating machine, comprises a body 10 and aremovable end plate 11. A multi-part work spindle 12 is mounted in body10 for rotation about axis 13. The particular spindle illustrated intubular and contains a cylinder chamber in which a piston 20 isreciprocable, the piston acting through a draw rod 30 to actuate a Workholding chuck that is mounted on the right end of the spindle (notshown). The spindle is mounted on a pair of axially spaced rollerbearings 14, of which only the hearing at the left end of the spindle isillustrated. The spindle is also rotatable about axis 13 on ball sleevebearings 15 and 16 within the index carrier unit, which in thisparticular embodiment is supported by the spindle. The carrier unitcomprises a Worm wheel 17 mounted on a bearing race ring 18, a faceclutch member 19 and a Geneva drive bracket 21 mounted on member 19.Rotatable on ball bearings 22 in the bracket there is a Geneva driver 23having at one end a drive pin 24 and at its opposite end a pinion 25.The pinion meshes with a gear 26 that is secured to the housing incoaxial relation with spindle 12.

Inner sections 27 and 28 of spindle 12 support for axial reciprocationthereon at Geneva driven wheel unit which comprises a tubular piston 29,a ring 31 and a face clutch member 32, all of which are coaxial with"ice spindle 12. The piston 29 is reciprocated by the alternateapplication of hydraulic pressure to annular chambers 33 and 34 that areformed between the piston and spindle sections 27, 28. The pressure isapplied through the respective passages shown schematically by brokenlines 35 and 36. Chambers 33 and 34 are sealed in a conventional mannerby O-rings disposed in annular grooves in the piston and in the spindlesections. Ring 31 carries a key 37 which connects it to the spindle 12for co-rotation therewith. Clutch member 32 has face clutch teeth 38meshing with complementary teeth 39 on clutch member 19. The teeth 38,39 taper in thickness in an axial direction, as shown in the lowerportion of FIG. 1, so that when member 32 is pressed axially to theright, by pressure in chamber 34, they mesh without backlash. The numberof teeth 33, and also of teeth 39, is a multiple of the number of teethto be cut in a work gear (not shown) mounted on the right end of thespindle. Member 32 has thereabout a plurality of equiangularly spacedradial slots 41, corresponding in number to the number of teeth of thework gear. These slots are adapted to receive and pass drive pin 24 (seeFIG. 2) when the Geneva driven wheel, 29, 31, 32, is in its left limitposition, wherein piston 29, FIG. 1, abuts flange 42 of spindle section28.

Clutch member 32 has an annular flange 43 which projects axially to theleft (in FIG. 1) and is interrupted by slots 44 that are aligned withand somewhat wider than slots 41. These slots 44 are adapted to pass alocking sector 45 on Geneva driver 23, diametrically opposite to pin 24.The flange 43 and sector 45 are of such length that they are engageablein any position of axial reciprocation of the Geneva driven wheel 29,31, 32.

In the particular gear generating machine of which the illustratedmechanism is a part, the carrier unit 17, 18, 19, 21 is rocked back andforth about axis 13 by a reversingly rota-ting worm (not shown) which ismounted in body 10 and drives the worm Wheel 17. As the carrier turnsclockwise (in FIG. 2), the pinion 25, FIG. 1, is rolled on stationarygear 26, and rotates the Geneva driver 23 clockwise relative to thecarrier. On the return rotation of the carrier the driver 23 rotatescounterclockwise. Throughout this rocking motion of the carrier,pressure in chamber 34 holds clutch teeth 38, 39 engaged so that thespindle 12 turns as a unit with the carrier, and the rotation of driver23 is idle, except in the latter part of the carriers clockwise rotationwhen pressure is applied to chamber 33 to disengage the clutch teeth andcause the drive to index the spindle relative to the carrier.

To achieve this periodic indexing a reversal of pressure to passages 35and 36 is effected by a reversing valve 46, FIGS. 1 and 4, that issupported by housing 10 and is actuated by a cam 47 on part 21 of thecarrier. The body 48 of valve 46 has ports 49 and 51 connectedrespectively to passages 35 and 36 by suitable conduits and a swivelconnection around spindle 12 (not shown). The valve body 48 also has apressure port 52 connected to a suitable source of hydraulic pressure,and two spaced exhaust ports 53 and 54. All of these ports open intovalve cylinder 55 in which a valve plunger 56 is slidable. The plungeris normally held in its left limit position (in FIG. 4) by a spring 57.It is moved to the right by cam 4'7, moving clockwise as indicated byarrow 58, the cam acting through lever 59, connector 61 and a rod 62rigidly connected to the plunger. The lever is pivoted by pin 63 to body48 and carries at its upper end a roller 64 engageable by the cam. Atits lower end the lever has a pin-and-slot connection 65 to connector61. The latter is slidable on rod 62 and confined between the head 67 ofthe rod and a washer 66 abutting spring 57.

In the normal spring-held position of the valve, circumferential grooves68 and 69 of plunger 56 respectively connect pressure port 52 to port 51(passage 36) and exhaust port 54 to port 49 (passage 35), so that theGeneva driven unit 29, 31, 32 is held in its right limit position, FIG.1, wherein clutch teeth 38, 39 are engaged. As the index carrier 17, 19,21 (turning in the direction 58, FIG. 4) approaches its clockwise limitposition, cam 47 abuts and moves roller 64 to the broken line position64, swinging lever 59 counterclockwise and causing connector 61 to moverod 62, 67, and plunger 56 to the right. In this position,circumferential groove 71 of the plunger connects exhaust port 53 topassage 36 and pressure port 52 to passage 35, causing the Geneva drivenunit 29, 31, 32 to be moved axially to the left in FIG. 1. The Genevadriver then advances the spindle 12, by one pitch of the work gear,relative to the carrier. When the cam has passed the roller and is inits terminal position shown in broken lines at 47, spring 57 returns thevalve and lever 59 to their normal positions, causing the Geneva drivenwheel to be returned to its position wherein clutch teeth 38, 39 areengaged. During return motion of the carrier, counterclockwise in FIG.4, the cam swings the roller 64 and lever 59 clockwise, but this iswithout effect upon the valve, the connector 61 merely sliding along rod62 against the compression of spring 57. When the cam has passed theroller the spring returns the lever and connector to the positionthereof shown in full lines in FIG. 4.

Considering the carrier 17, 19, 21 to be the body of reference, and thedriver 23 to be rotating clockwise in FIG. 2, the indexing action is asfollows: On each turn of the driver the sector 45 passes idly throughthe right and left slots 44. The valve actuating cam 47 is in such phasein relation to rotation of the driver that pressure is applied tochamber 33 to shift the Geneva driven wheel to the left in FIG. 1 justas the sector has entered the left slot 44, whereby the sector holds thedriven wheel (and spindle 12) against rotation while the shifting isoccurring and while, momentarily, the clutch teeth 38, 39 are disengagedand the pin 24 is not yet engaged with a slot 41.

As the sector 45 leaves the left slot 44, the position shown in FIG. 2,the pin 24 enters the right slot 41 and during the ensuing one-half turnof the driver 23, indexes the driven wheel 29, 31, 32 and the spindlecounterclockwise by one pitch. This indexing action occurs in the smoothmanner usual in Geneva motions by reason of the pin 24 entering anddeparting the slot 41 tangentially. As the pin leaves slot 41 the sector45 enters the slot 44 then at the right in this view. At this time thecam 47 has just passed the roller 64 and the spring 57 has returned thevalve to its normal position, so that now pressure is applied to chamber34, shifting the Geneva driven wheel to the right (in FIG. 1) andengaging the clutch teeth 38, 39 while the wheel is being held againstrotation by the sector.

By angularly adjusting the drive to worm wheel 17 to reposition theangle through which the carrier 17, 21 oscillates relative to housing10, the mechanism illustrated may be made to index at any desiredposition of clockwise rotation of the carrier. For example, if the angleis so repositioned that cam 47 is in the position shown in full lines inFIG. 4 near the beginning of clockwise rotation of the carrier, thenindexing will occur in the early part of such clockwise rotation, ratherthan in the latter part thereof as described above. Also, by replacingvalve 46 with a valve of opposite hand and repositioning the angle ofcarrier oscillation relative to housing 10, the mechanism may be made toindex at any desired phase of counterclockwise rotation of the carrier.

Having now described the preferred embodiment of my invention and itsmode of operation, what I claim is:

1. An index mechanism comprising a carrier, a spindle rotatable in thecarrier, a Geneva driven wheel co-rotatable with the spindle and havingequiangularly spaced radial slots and also similarly spaced clutchteeth, the carrier having mating clutch teeth, a Geneva driver rotatablein the carrier on an axis parallel to the spindle and having a drive pinengageable in the slots of the wheel, said driver being adapted toadvance the wheel by one pitch upon each rotation thereof in which thepin engages one of said slots, and means to shift the wheel axially inthe carrier between (a) a first position wherein the clutch teeth of thewheel and carrier are engaged and the wheel is unengageable by the driveand (b) a second position wherein the clutch teeth of the wheel andcarrier are disengaged and the pin of the driver is engageable with saidslots.

2. A mechanism according to claim 1 in which said face clutch teeth areof tapering thickness in an axial direction so that in said firstposition of the Wheel said teeth may engage without backlash.

3. A mechanism according to claim 2 in which the means to shift thewheel comprises a member for exerting an axially directed pressureagainst the wheel to maintain such engagement without backlash while thewheel is in said first position.

4. A mechanism according to claim 3 in which the means to shift thewheel include a piston member movable in a cylinder chamber in a membercoaxial of the spindle, one member being integral with the wheel and theother member being supported against axial motion relative to thespindle.

5. A mechanism according to claim 4 in which the spindle is supportedagainst axial motion in the carrier, the wheel is axially movable on thespindle, and said other member is integral with the spindle.

6. A mechanism according to claim 1 in which there are formations on thewheel and driver which engage to hold the wheel against rotation beforethe pin enters and after it departs from a slot of the wheel and whichare disengaged while the pin is engaged in a slot, said formations beingengageable in any position of axial shifting motion of the wheel.

7. A mechanism according to claim 6 in which said formations comprise anaxially projecting annular flange on the Wheel having therearound spacedradial slots aligned with the first-mentioned slots and further comprisean axially projecting sector on the driver adapted to enter one of theslots in the flange as the pin leaves an adjacent first-mentioned slot,and to depart from a slot of the flange as the pin enters an adjacentfirst-mentioned slot, the sector during each complete turn of the driverpassing through two adjacent slots of the annular flange, the axiallengths of the sector and flange being such that said passing engagementoccurs in any position of axial shifting of the wheel.

8. A mechanism according to claim 1 having a housing in which saidcarrier is rotatable about the axis of the spindle, and gearing betweenthe housing and driver for rotating the latter by and upon rotation ofthe carrier in the housing.

9. A mechanism according to claim 8 in which said means to shift thewheel axially are operable by and upon rotation of the carrier in thehousing.

10. A mechanism according to claim 9 in which said means to shift thewheel axially are fluid pressure operated and include valve meansoperable by and upon rotation of the carrier into predetermined relationto the housing.

References Cited by the Examiner UNITED STATES PATENTS FRED C. MATTERN,JR., Primary Examiner.

1. AN INDEX MECHANISM COMPRISING A CARRIER, A SPINDLE ROTATABLE IN THECARRIER, A GENEVA DRIVEN WHEEL CO-ROTATABLE WITH THE SPINDLE AND HAVINGEQUIANGULARLY SPACED RADIAL SLOTS AND ALSO SIMILARLY SPACED CLUTCHTEETH, THE CARRIER HAVING MATING CLUTCH TEETH, A GENEVA DRIVER ROTATABLEIN THE CARRIER ON AN AXIS PARALLEL TO TH SPINDLE AND HAVING A DRIVE PINENGAGEABLE IN THE SLOTS OF THE WHEEL, SAID DRIVER BEING ADAPTED TOADVANCE THE WHEEL BY ONE PITCH UPON EACH ROTATION THEREOF IN WHICH THEPIN ENGAGES ONE OF SAID SLOTS; AND MEANS TO SHIFT THE WHEEL AXIALLY INTEETH OF THE WHEEL AND CARRIER ARE ENGAGED AND THE WHEEL IS UNENGAGEABLEBY THE DRIVE AND (B) A SECOND POSITION WHEREIN THE CLUTCH TEETH OF THEWHEEL AND CARRIER ARE DISENGAGED AND THE PIN OF THE DRIVER IS ENGAGEABLEWITH SAID SLOTS.